Grinding from rear

[Jay-ZS+]

Last few weeks Ive noticed a grinding sound coming from what sounds like the rear nearside wheel.

Thing is it only happens when Im hammering it round a roundabout and the car has a fair bit of roll. First I thought it was a bearing but doesnt happen at speed in a straight line. Also crossed my mind it could be the tyre rubbing but the car isnt lowered and it sounds more mechanical. Prehaps a loose brake guard??

Just wondered if anyone had any ideas what to look for?